Using sulcal basins for analyzing functional activations patterns in the human brain

Abstract

In previous work, we have introduced the concept of sulcal basins. Sulcal basins are subdivisions of cortical folds that allow to establish a complete parcellation of the cortical surface into separate regions. In this paper, we present methods of using this concept to support the analysis of functional activation patterns in the human brain as measured by fMRI (functional magnetic resonance imaging) experiments. In particular, we present two methods of performing inter-subject averages. The first method uses a form of non-linear spatial normalization based on sulcal basin landmarks. The second method performs group averages using sulcal basins themselves as entities for averaging. This second approach has the advantage of ensuring that truly anatomically homologue entities enter the averaging process. In addition, it yields results that are immediately interpretable by a specialist. The methods are presented in the context of an fMRI experiment in which 10 test subjects were asked to respond to various visual stimuli.